And you thought it was Hal Holbrook all these years!
Former understudy to J Edgar Hoover, 91 year-old W Mark Felt has been outed today as Deep Throat.
Story from the Washington Post following the revelation in the latest edition of Vanity Fair. Yes, Wikipedia has a developing page on Mr Felt, though at this stage no clues as to what the W stands for. Nothing as I write this on the website of his former employer.